The objectives of this project are to use human adenoviruses and adenovirus-SV40 hybrid viruses as tools to study the genetics of DNA tumor viruses; to define the role of viral genes and viral antigens in viral induced tumors and to study the biology of adenovirus-SV40 hybrid viruses. Due to the lack of proper facilities to pursue studies with nondefective adenovirus 2 SV40 hybrids during the past 4 years, the major emphasis of the project has gradually shifted to a study of the oncogenic properties of human adenovirus type 2. BIBLIOGRAPHIC REFERENCES: Breeden, J.H., Wewerka-Lutz, Y., Schnipper, L.E., Hauser, J., Patch, C.T., Lewis, A.M., Jr., and Levine, A.S.: Content and expression of integrated viral DNA in hamster cells transformed by nondefective adenovirus type 2 simian virus 40 hybrid viruses. J. of Virol., 20: 555-563, 1976. Tevethia, S.S. and Lewis, A.M., Jr.: Two adenovirus type 2 simian virus 40 hybrid populations which contain the entire SV40 genome differ in their ability to induce SV40 transplantation immunity in hamsters but not in mice. J. of Virol., 20: 539-542, 1976.